Microlepidoptera and birch sawfly (Tenthredinidae) leaf miners were studied from 1986 to 1990 in polluted areas in the region of Bratsk-city, Siberia, Russia. The principal pollutants were fluorine and sulfur dioxide which had average annual concentrations of 0.01 to 0.11 mg/cubic m. and 0.03 to 0.26 mg/cubic m., respectively. We determined the percentage of trees with damaged leaves to estimate abundance in order to characterize the population density dynamics of species in these groups of leafminers.
Principle findings were: (1) For the sawflies, the range of variation abundance was higher in areas with high levels of pollution (79 % in a fluorine polluted area and 63 % in a sulfur polluted area compared to 45 % in an undisturbed area). The average abundance of sawflies was usually higher in the polluted areas than in the unpolluted one. (2) For Microlepidoptera, the abundance of individual species was affected by high levels of air pollution in different ways; the abundance of Paronix betulae Stl. (Gracillariidae) and Leucoptera scitella L. (Lyonetiidae) increased whereas Phyllonoryeter apparella H.S. (Gracillariidae) decreased. P. populifoliella Tr. and Eriocrania sp. showed maximum abundance when the concentrations of pollutants were at average levels. (3) The highest variations of abundance among all of the leafminers were in P. betulae L., scitella and the birch sawflies.
When forestry is conducted in disturbed and polluted ecosystems, it is important to consider individually the population dynamics of each species of insect there.
Key words: leafminers, microlepidoptera, sawflies, pollution.
Correspondence: Andrey V. Selikhovkin, Forest Technical Academy, Institutski per 5, Saint Petersburg 194018, Russia
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E-mail: sel@zisp.spb.su